To compare the lingual region upper airway CT scan results of OSAS patients and normal adults to explore if there are upper airway stricture in OSAS patients and the reason of stricture. 59 patients with OSAS and 57 normal adults were included in the study. CT evaluated the lingual region upper airway with the use of a Philips Tomoscan AV Expander E1 spiral scanner. The shapes of lingual region upper airway were observed. The area and the dimensions of lingual region was studied, and the thickness of retropharyngeal and lateral pharyngeal tissue were evaluated too. The another focus area was tongue, and the evaluated data included the tongue width, genioglossus width, hyogolssus width, tongue length and tongue area. The data comparative results of OSAS and normal groups were as follows: the right to left diameter and area of OSAS patients' lingual region upper airways were less than those of normal adults, the thickness of lateral pharyngeal, tongue width, genioglossus width, hyogolssus width and tongue area